Re: new job =(
I think you should talk to people around you more at work. Be social and make an effort to get to know your department, the culture there, expectations, employees, etc. I completely understand the nervous feeling you're getting though...its tough being the newbie...not knowing the rules, people, environment, etc. But dont let that stop you from making that place your own...you're also an employee there and part of your job entails making sure you can work cohesively with others.
Dont let this girl bother you...be friendly to her and understand her attitude is stemming from a place of insecurity. After all, she is about to be replaced by you and if she has picked up on it...then she might be a bit upset. Its not your fault or problem though so dont let her stop you from moving ahead in life.
Much luck!
:)